The present invention relates generally to a system for spreading flexible material, and more particularly to an automatic system with reload capability for spreading multiple layers of material, such as fabric, in selective spread lengths over a table surface.
For example, in the garment industry individual clothing items are formed by joining various pieces of fabric or cloth materials. The majority of the several pieces comprising a garment of a given size must be cut to corresponding shapes. In times past, each piece of fabric was simply cut with scissors from a length of material. This highly labor intensive approach has been replaced by the simultaneous cutting of multiple layers of fabric, with an electric knife for instance, to produce multiple garment pieces of the desired size and shape. Industries other than the garment industry also utilize the technique of cutting or stamping a plurality of workpieces from multiple layers of material. This results in significant labor and cost savings in the production of finished goods.
Nonetheless, a substantial amount of labor is still required to properly arrange the multiple layers of material for subsequent operations. This can be a time-consuming process since fabric and other types of flexible material can be easily damaged, and therefore requires careful handling. Thus, costs of a different nature are incurred in arranging the layers of material manually, or at best semi-automatically. The problem is further compounded by the fact that many types of flexible material are typically produced and sold in large bolts. These bolts of rolled material may weigh up to several hundred pounds or more and are therefore extremely difficult to handle either manually or semi-automatically.
The present invention comprises an automatic system for spreading material which overcomes the foregoing and other problems long since associated with the prior art. Although the invention is particularly useful for spreading cloth or fabric materials, it will be understood that the invention can be utilized to spread any flexible material including plastic and paper. In accordance with the broader aspects of the invention, the system includes a carriage onto which a roll or bolt of material is loaded. The carriage comprises a movable spreader which straddles a fixed table. An antitension loop is maintained in the material as it is fed onto the table surface from the bolt during travel of the carriage. Catcher assemblies are located on the table at each end of the desired spread length to catch the loop of material each time the carriage reverses direction. Cutting means within each catcher assembly function to sever the end loops between adjacent layers of material. A microprocessor mounted on the carriage is utilized to control the system. By means of the invention, multiple layers of material can be spread automatically and rapidly from a reloadable bolt of material.
In accordance with more specific aspects of the invention, the system preferably comprises a storage and loading portion in conjunction with a spreading portion. The storage and loading portion is positioned above the spreading portion, preferably on a mezzanine level. Bolts of material each having an arbor shaft introduced through the core thereof are loaded on a conveyor for advancement toward an elevator assembly. The conveyor indexes successive bolts into engagement with an escapement assembly which places the leading bolt onto a spaced pair of fixed elevator arms. The bolt of material is then carried by the elevator assembly downward through an opening in the mezzanine floor to the spreading portion of the system. The storage conveyor is responsive to photosensors which detect the presence of bolts of material with arbor shafts therein to prevent the inadvertent advancement of a bolt lacking an arbor shaft through the elevator opening in the mezzanine floor. Preferably, a trap door assembly is mounted across the elevator opening to positively close the opening except during movement of the elevator assembly.
The spreading portion of the system includes a fixed table, two catcher assemblies mounted at spaced locations on the table, and a movable carriage straddling the table. Before loading the fresh bolt of material onto the carriage, a pair of pivotal transfer arms on the elevator assembly effect removal of the empty arbor shaft from the carriage. The fresh bolt is then placed in cradles on the carriage, after which the elevator assembly moves upward to receive the next bolt of material after dropping the empty arbor shaft from the previously spread bolt into a receptacle on the mezzanine level for collection and reuse.
With a bolt of material loaded and threaded on the carriage, the material is then spread over the fixed table. The carriage straddles the table and is supported on wheels driven by a hydrostatic drive system. The amount of material maintained in a tensionless loop on the carriage is monitored by photosensors. The rate of material feed as well as the rate of travel of the carriage is responsive to the monitored amount of material maintained in the antitension loop so that material is spread at the fastest rate without damaging the material.
The material is spread over the table between the catcher assemblies by the carriage. If desired, one of the catcher assemblies can be removably attached to the table at any one of several predetermined locations therealong to provide for different material spread lengths. A positional feedback assembly generates appropriate signals for use by a microprocessor in controlling the carriage as it reciprocates over the table between the catcher assemblies. Pivotal bars in each catcher assembly engage the loop of material formed when the carriage reverses direction to prevent the material from following. A rotating blade in each catcher assembly then separates adjacent layers of spread material as the carriage travels toward the other catcher assembly. The spreading operation continues without interruption until the bolt carried by the carriage is depleted, at which time the carriage parks beneath the elevator assembly for reloading. Preferably, the fixed table includes an output conveyor positioned beneath a false top so that a previous spread of material can be advanced into a subsequent work station during operation of the system.